1. Field of the Invention
The present invention relates to a smoking article and a wrapper for a smoking article that provide substantially reduced ignition propensity in the smoking article, particularly in the case of a cigarette. When a smoking article, such as a cigarette, employing the wrapper of the invention is dropped or left on a flammable substrate, the cigarette tends to self-extinguish before igniting the flammable substrate.
2. Description of the Prior Art
There is a recognition in the industry that the smoking article wrapper has a significant influence on the reduction of ignition propensity. Several solutions have been proposed to solve the problem of providing a low ignition propensity cigarette involving modification of the porosity of the smoking article wrapper.
For example, it is known that the burn characteristics of a wrapper can be modified by adding fillers, coatings or additives to the wrapper. U.S. Pat. No. 4,480,650 to Weinert discloses a self-extinguishing cigarette in which the interior surface of the wrapper is coated with clay. U.S. Pat. No. 4,889,145 to Adams et al. discloses a cigarette wrapper having an area containing a discontinuous coating of porosity reducing composition. U.S. Pat. No. 4,615,345 to Durocher discloses a cigarette having cross-directional or circumferential bands treated with burn promoter wherein the untreated paper does not support combustion and the cigarette self-extinguishes when the cigarette burns into the untreated area of the wrapper. U.S. Pat. No. 4,453,553 to Cohn attempts to improve upon both sidestream smoke characteristics and fire resistance by the use of longitudinal stripes of burn rate reducing substances and optionally an additional layer of cigarette wrapper paper.
Modification of the smoking article wrapper by the modifying the base paper properties in certain regions or applying to the base paper a cross directional ring or piece of paper having different properties than the base paper have been proposed. U.S. Pat. No. 4,945,932 to Mentzel et al. discloses a cigarette wrapper paper having annular zones of low permeability formed by a batonneing process. U.S. Pat. No. 4,739,775 to Hampl, Jr. discloses the application of circumferential bands of paper having reduced filler content onto the inside of the base paper to form smoking articles that are self-extinguishing in the two layer circumferentially banded zones. U.S. Pat. No. 5,474,095 to Allen et al discloses a wrapper paper having cross-directional or circumferential regions with increased basis weight that is produced in the papermaking process by depositing additional material onto the base web in the papermaking machine using a drum containing a plurality of slits.
The use of chemical additives described above to form longitudinal strips is undesirable as to the potential effects of the chemicals, as is the cost and effort involved in use of complex papermaking equipment to influence the physical properties of the paper by decreasing permeability in longitudinal strips along the paper.
It would be desirable to provide a simple, easy to manufacture smoking article having a reduced ignition propensity which does not require the use of extensive process modifications and/or additional processing equipment, chemical additives or the like in its manufacture. It would also be desirable to provide a smoking article having a reduced ignition propensity that could be made with the use of readily available, conventional materials and with existing process equipment, without sacrificing the look, feel, taste and burn of a conventional cigarette.
It would also be desirable to provide a smoking article with a reduced ignition propensity as well as an increased puff count over a conventional smoking article with the same tobacco rod content and physical characteristics.
The invention provides smoking article having a reduced ignition propensity which is also easy to manufacture. The smoking article of the invention does not require the use of extensive process modifications and/or additional processing equipment, or a requirement for chemical additives or the like in its manufacture. The invention also provides a reduced ignition propensity smoking article having an increased puff count for a given tobacco rod.
The smoking article and the smoking article wrapper of the invention provide smoking articles having reduced ignition propensity. The smoking article of the invention comprises a rod of smokable material, such as tobacco, disposed in a wrapper and having a first end, a second end opposed to the first end and a longitudinal axis extending from the first end to the second end. The wrapper comprises a strip of paper material forming a region having at least two paper layers aligned substantially parallel to the longitudinal axis. The paper material for one of the layers may be tobacco paper.